I know exactly how you feel. I also am not old and don't look ill most of the time. My regular Dr. even commented on it. I also have a very obvious limp in the morning and when I sit for any length of time. It wears off pretty fast. I actually do not have any visable signs except for my knees (when they are swollen). They are usually covered anyway. I rarely swell anywhere else. I get really sick of people saying "you look fine". I do not even try to convince anyone. My husband mentioned to my Dr. that I was a hypocondriac (Bad spelling),  My dr. replied that I had serious health problems. I guess that made a believer out of my husband. He had forgotten the winter of 2007, when I did not leave the house for months and he took care of everything. Or the fact that I hurt so much, could hardly walk and he would get me up out of bed and walk me around the house. Good Luck to you